Self-starter system for single rotor rotary expansion engine

ABSTRACT

The self-starter system for a single rotor, rotary expansion engine of the planetary rotor type which is rotatively driven by pressurized fluid comprises conduit means connected to the source of pressurized driving fluid and a pressure responsive valve for controlling flow of pressurized fluid through the conduit means so as to pass pressurized fluid to the working chambers of the engine where such pressurized fluid acting on the rotor generates a torque force which rotates the rotor to a position for selfsustained rotation of the rotor.

Unite States atent [19] Chen et a1.

[ 1 Nov. 12, 1974 1 SELF-STARTER SYSTEM FOR SINGLE ROTOR ROTARY EXPANSION ENGINE [75] Inventors: Hsin S. Chen, Hasbrouck Heights;

Charles Jones, Hillsdale, both of NJ.

173] Assignee: Curtiss-Wright Corporation,

Wood-Ridge, NJ.

22 Filed: Nov. 19, 1973 21 Appl. No.: 416,929

[52] US. Cl 418/15, 418/61 A, 60/596 [51] Int. F016 l/02, F040 1/02, FO4c 17/02 [58] Field of Search 418/61 A, 15, 181; 60/596;

[56] References Cited UNITED STATES PATENTS 2,849,857 9/1958 Davids 123/179 F 3,146,765 9/1964 Bush 60/596 3,182,650 5/1965 Heckt.... 123/179 F 3,628,899 12/1971 George 418/61 A Primary Examiner-John J. Vrablik Attorney, Agent, or Firm-Arthur Frederick [57] ABSTRACT The self-starter system for a single rotor, rotary expansion engine of the planetary rotor type which is rotatively driven by pressurized fluid comprises conduit means connected to the source of pressurized driving fluid and a pressure responsive valve for controlling flow of pressurized fluid through the conduit means so as to pass pressurized fluid to the working chambers of the engine where such pressurized fluid acting on the rotor generates a torque force which rotates the rotor to a position for self-sustained rotation of the rotor.

12 Claims, 9 Drawing Figures PAIENTEDNBVIZIBM 3'847'514 sam'anra PATENTEDHDV 12 m4 sum not A SELF-STARTER SYSTEM FOR SINGLE ROTOR ROTARY EXPANSION ENGINE This invention relates to single rotor, rotary expansion engines of the planetary rotor type and, more particularly, to a self-starter system for such engines which does not require a source of power different from that which drives the engine. In single rotor rotary expansion engines as exemplified in the US. Pat. to George No. 3,628,899 and British Pat. No. 8949 to Phippen, means must be provided to start the engine when the rotor is in a position such that the forces acting onthe rotor by the pressurized fluid are in equilibrium or when pressurized fluid intake valves are closed. One solution to this problem is to provide a small by-pass conduit to conduct pressurized driving fluid into a working chamber of the engine wherein such fluid will exert a torque on the rotor and effect rotation of the latter to a position where sustained rotation can be achieved by the passage of pressurized driving fluid through the intake ports. This solution is disclosed in the aforesaid British patent which also discloses a manually operative valve for controlling flow through the by-pass conduit. In certain applications of an expansion engine, such as a prime mover for operatorless device, a manually operated valve is impractical. In such use of the expansion engine an automatic self-starter system is essential.

Accordingly, it is an object of this invention to provide a self-starter system for a single rotor, rotary expansion engine which system is fully automatic.

Another object of the present invention is to provide a self-starter system for a single rotor, rotary expansion engine, which system is operable in response to pressurized driving fluid to pass such fluid into the working chambers of the engine to cause the rotor to turn.

A further object of this invention is to provide, in a single rotor, rotary expansion engine, a self-starter system which is capable of effecting rotation of the rotor even though such rotor is in a position where pressurized fluid entering the intake ports exert on the rotor counterbalancing forces or when the intake ports are closed.

A still further object of the present invention is to provide in a single rotor, rotary expansion engine, a self-starter system which automatically becomes inoperative after a short interval of time.

SUMMARY The present invention, therefore, contemplates a self-starter system for a single rotor, rotary expansion engine of the planetary rotor type, such as disclosed in the US. Pats. to George, No. 3,628,899 and Pratt No.

3,452,643 and the British Pats. to Phippen, No. 8949, Maillard No. 583,035 and Linder No. 989,588.

The expansion engine has a housing having a cavity within which a multi-lobe rotor rotates with and about an eccentric portion of a crankshaft to drive the latter. The rotor and housing are so constructed that they define a plurality of working chambers which successively increase and decrease in volumetric size as the rotor planetates relative to the housing cavity. The housing is provided with intake port means which communicate with a source of pressurized driving'fluid to pass such fluid into the working chambers. Exhaust port means is also provided in the-housing to pass spent pressurized driving fluid from the working chambers. To properly time the introduction of pressurized fluid (such as the gaseous product of a chemical reaction, steam or other pressurized fluid) through the intake port means and into the working chambers, a valve means is provided, which valve means is operatively connected to the rotor to open and close in synchronism with angular position of the rotor. As an example, the expansion engine may be of the Wankel type comprising a rotorof generally triangular configuration in profile disposed for eccentric rotation in a housing cavity having an epitrochoidal shape so that the rotor and housing define three working chambers. In such an engine it is contemplated that two intake and two exhaust ports be provided so that there are six power impulses per rotor revolution in an engine having a 3:] drive rotor between the crankshaft and rotor, the flow of pressurized fluid through the intake ports being controlled by valves.

The self-starter system comprises a conduit means which communicates at one end with the source of pressurized driving fluid and at least with one of the working chambers which is substantially fluid tight, the pressurized fluid exerting a torque force on the rotor. Also, a valve means is disposed in the conduit means for controlling pressurized driving fluid flow therethrough. The valve means is so constructed and arranged that it responds to pressurized fluid to move from a closed position to an open position, in which position it pennits flow of pressurized driving fluid therethrough and into the one working chamber.

In a narrower aspect of the present invention the selfstarter system comprises a valve means of the piston or shuttle type which has a piston disposed for reciprocative movement in a housing cavity to control flow through the port means in the housing. A biasing means is provided to bias the piston in an initial or starting position where the port means is open. The housing cavity is in communication with the source of pressurized fluid so as to apply a force on the piston in a direction toward closing the port means. The valve also includes a restricted fluid passageway which vents the housing cavity ahead of the piston. When pressurized driving fluid is flowed through the valve port means it is simultaneously delivered to two working chambers one of which is substantially fluid tight so as to exert a torque force on the rotor. This rotationof the rotor insures that it is not in an equilibrium position and insures that at least one intake valve is actuated to an open position and that self-sustained rotor rotation will be achieved. It is possible by proper sizing of the valve means and its ports as well as the passageway means for delivering pressurized gaseous fluid to the working chambers to provide a piston movement of a predetermined duration such that several injections of pressurized fluid into the working chambers are made as the rotor rotates to insure self-sustained rotor rotation.

In another embodiment of the present invention the valve means includes a piston disposed for reciprocative movement in a housing cavity to control flow of fluid through two ports in the housing. The piston is biased in a closed position by a biasing means so that the two ports are initially closed. The housing cavity is in communication with the source of pressurized fluid so as to apply a force on the piston in a direction to move the piston against the force of the biasing means to suecessively open the two ports. The valve means also includes aretracted fluid passageway 01' vent which prevents fluid from being trapped in the cavity ahead of the piston. During the time the valve means is moving, pressurized driving fluid flows successively through the conduit means into the working chambers, the rotor being rotated when the pressurized fluid is delivered to a working chamber which is substantially fluid tight and such pressurized fluid is able to exert a torque force on the rotor. This rotation of the rotor insures that it is not in an equilibrium position and insures that at least one intake valve is actuated to an open position for effecting self-sustained rotor rotation by admission of pressurized fluid through the intake ports.

BRIEF DESCRIPTION OF THE DRAWINGS The invention will be more fully understood from the following description thereof when considered in connection with the accompanying drawings wherein but one embodiment of the invention is illustrated by way of example and in which:

FIG. 1 is a schematic illustration of the self-starter system for a single rotor, rotary expansion engine according toone embodiment of this invention;

FIGS. 2 to 5 are views, similar to FIG. 1, showing various sequential steps in the operation of the self-starter system shown in FIG. 1;

FIG. 6 is a schematic view of the self-starter system according to another embodiment of this invention; and

FIGS. 7, 8 and 9 are views similar to FIG. 6, showing various other possible starting positions of the rotor.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Now referring to FIG. 1, the reference number 10 generally designates the self-starter system according to one embodiment of this invention which functions to effect start-up of a single rotor, rotary expansion engine 12.

The expansion engine 12 is of any suitable construction and may be of the design disclosed in the US. Pat. No. 3,628,899 to George and No. 3,452,643 to Pratt and the British Pat. No. 8949 to Phippen. The expansion engine 12 may be of the Wankel type as schematically shown in the drawings, which engine 12 comprises a housing 14 defining an epitrochoidal shaped cavity in which a triangular shaped rotor 16 is eccentrically supported for rotation on a crankshaft 18. The rotor 16 defines with the housing a plurality of working chambers A, B and C. Each of these working chambers successively expand and contract in volumetric size as rotor 16 rotates within the cavity of housing 14. To provide for six power impulses for every revolution of rotor 16 where the drive ratio between crankshaft 18 and rotor 16 is 311, a pair of spaced intake ports 22 and a pair of spaced exhaust ports 24 and 24A are provided. An intake manifold 25 may be provided to receive pressurized driving fluid from a source thereof (not shown) through a supply conduit 26. The intake manifold 25 is connected to each of the intake ports 22 via passageway means or branch conduits 27 and 29. To control fluid flow through intake ports 22, valve. 28 and 28A are disposed at each of the intake ports 22, which valves are suitably connected to rotor 16 so that valves 28 and 28A open and close in relation to the angular position of the rotor to admit and stop flow of pressurized fluid flow into working chambers A, B and C at proper times. As shown in the US. Pats. to George, Jr.

No. 3,762,842, and Pierce, et a], No. 3,744,940, intake valves may be of the rotary type interconnected for coordinated movement with the rotor 16 in a manner also as shown in the aforesaid patents. In the case of the engine being a prime mover for an operatorless device, the source of pressurized fluid may be a combustion or reaction chamber (not shown) where a mixture chemically reacts to produce a gaseous fluid. The source of pressurized fluid in other applications might be a steam or gas generator or other generating apparatus for pressurizing a liquid or gas. Each of the exhaust ports 24 and 24A may be connected to a manifold (not shown) and an exhaust pipe (not shown) to conduct spent fluid from the working chambers A, B and C of the expansion engine.

If the rotor 16 is in the position shown in FIG. 1, where intake valves 28 and 28A are closed, the pressurized fluid cannot enter working chambers A, B or C and therefore the engine would remain inoperative after receiving pressurized fluid. Even if valve 28 is slightly open to admit pressurized fluid into chamber A, rotor 16 would still not rotate since such fluid exerts counterbalancing torque forces on the rotor. There are also rotor positions where an intake valve is open but the pressurized fluid acting upon rotor 16 fails to produce a torque force or one of sufficient magnitude to rotate rotor 16. It is, therefore, essential to provide expansion engine 12 with self-starter system 10.

The self-starter system 10 comprises a valve 30 having a housing 32 in which a piston 34 is disposed for reciprocative movement. The piston has an annular groove 36 which forms two land portions 38 and 40. The housing 32 has a first inlet port 42 and a second inlet port 44. An outlet port 46 is also provided in housing 32. A first passageway means or conduit 48 is connected to valve 30 to communicate at one end with outlet port 46 and, at the opposite end, with chamber B. A second passageway means or conduit 50 is connected to pipe 48 so as to communicate outlet port 46 with chamber C. The first and second inlet ports 42 and 44 are respectively connected by passageway means or pipes 54 and 56 to supply conduit 26' so as to conduct pressurized fluid to inlet ports 42 and 44. The first and second conduits 48 and 50 and pipes 54 and 56 are of small flow area as compared with the flow area of manifold 25, conduits 27 and 29, valves 28 and 28A and intake ports 22. The conduits 48 and 50 while of small flow area are of a size so as to provide sufficient pressurized fluid flow for turning rotor 16 at low speed and to act as flow limiters when pressurized fluid is being discharged through the exhaust ports 24 and 24A. A biasing means which may be in the form of a spring 52 is disposed within valve housing 32 to bear against piston 34 and the housing and force piston 34 to the left as viewed in FIG. 1. In this position annular groove 36 is aligned with inlet port 42 and outlet port 46 so that inlet port 42 and outlet port 46 are in communication. This piston position provides, therefore, when pressurized fluid is flowed through supply conduit 26, for flow of pressurized fluid simultaneously to conduits 48 and 50, via pipe 54, groove 36, and outlet port 46. Thus, pressurized fluid is conducted simultaneously to working chambers A and C by way of conduits 48 and 50, respectively. Also pressurized fluid is conducted by pipes 54 and 56 to inlet port 44 where the pressurized fluid enters the valve housing cavity so as to actagainst the end surface 58 of piston 34 and exert a force on the piston opposite to that of the force exerted on the piston by spring 52. The portion of housing cavity 60 in which spring 52 is located is vented to a low pressure area via a pipe 62 which is either provided with a restricting orifice 64 or has a very small flow area relative to the flow area of inlet port 44 so that the flow of gas through pipe 62 is at a slow rate and thereby cushions the piston and controls the speed of movement of piston 34. By sizing of the orifice 64 or pipe 62 the speed of piston 34 can be controlled to a predetermined value and thereby provide a predetermined multiplicity of impulsesto rotor 16 for a preselected number of rotor revolutions.

As best illustrated in FIG. 1, self-starter system functions in the manner hereinafter explained following the introduction of pressurized fluid into supply conduit 26 from a suitable source thereof (not shown). From supply conduit 26, the fluid flows, through manifold 25, branch conduits 27 and 29, to intake valves 28 and 28A. Assuming intake valves 28 and 28A are in the closed positions as shown in FIG. 1, pressurized fluid cannot enter chambers A, B WC and, hence, the engine cannot start. However, simultaneously with flow of pressure fluid through conduits 27 and 29, pressurized fluid flows through pipes 54 and 56 to first and second inlet ports 42 and 44 of valve 30. The pressurized fluid entering first inlet port 42 of valve housing 32 passes through outlet port 46 into conduits 48 and 50 and thence into working chambers B and C. The pressurized fluid entering working chamber B is not effective to rotate rotor 16 because the pressurized fluid discharges from working chamber B through exhaust port 24A. However, working chamber C is, at this time, a substantially fluid tight chamber; that is it is not in communication with either exhaust port 24 or 24A. Therefore, the pressurized fluid entering working chamber C exerts on rotor 16 a torque force in a clockwise direction as is shown by the arrow T. This torque force rotates rotor 16 which, because of the synchronized interconnection (not shown) between intake valves 28 and 28A and rotor 16, actuates the valves so that valve 28 opens to admit pressurized fluid into working chamber A (see FIG. 2). The pressurized fluid in working chamber A exerts a torque force on rotor 16 to rotate the latter in a clockwise direction. As shown in FIG. 3, the rotor is now moved to where intake valve 28 is again closed and working chamber C is about to communicate with exhaust port 24. Also, during this time, the pressure of the fluid passing into valve through inlet port 44 is exerting on end surface 58 of piston 34 a force sufficient to overcome the force exerted on piston 34 by spring 52. This imbalance of forces acting on piston 34 moves the piston to the right as viewed in FIG. 1 where outlet port 46 is being closed. However, outlet port 46 remains open at least for a duration of time sufficient to supply pressurized fluid to working chamber A via conduit 48 when rotor 16 is in the position shown in FIGS. 4 and 5. By this time rotor 16 is achieving rotation by pressurized fluid entering intake ports 22 at the times as controlled by intake valves 28 and 28A. The piston 34 by the time the rotor begins open through one or more additional 180 of rotation of crankshaft 18. So long as pressurized fluid is supplied to supply conduit 26 piston 34 will remain closed. In most applications expansion engine 10 must be capable of restarting after it is stopped. If the expansion engine 10 is stopped, spring 52 will return valve 34 to the open position shown in FIG. 1 as the pressurized gaseous fluid escapes from conduits 26, pipes 54 and 56 and valve 30 or is released through a suitable manual valve (not shown). With valve 30 in the position shown in FIG. 1, restarting is achieved by the re-introduction of pressurized fluid into supply conduit 26 and the engine is restarted in the same manner as previously described. If the rotor is stopped in the position shown in FIG. 5, restarting is achieved by pressurized fluid in working chamber A providing the torque force for turning the rotor rather than the pressurized fluid entering working chamber C.

In FIGS. 6, 7, 8, and 9, a self-starter system constituting another embodiment of this invention is illustrated. The self-starter system 70 essentially differs from self-starter system 10 in that the valve 30 of selfstarter system 70 provides for sequential flow of pressurized fluid to the working chambers rather than simultaneous flow of pressurized fluid to the working chambers as provided for in self-starter system 10. The parts of self-starter system 70 which correspond to like parts of self-starter system 10 will be designated by the same reference numbers in the following description.

As shown in FIG. 6, valve 30 has two spaced outlet ports 74 and 76 which, respectively, communicate with conduits 48 and 50. The intake port 42 is of enlarged size in relation to intake port 42 of self-starter system 10 (FIG. 1) so as to effect alternate communication with outlet ports 74 and 76 for a relatively great movement of piston 34.

In operation of self-starter system 70, when pressurized fluid is initially delivered to supply conduit 26, piston 34 is in the position shown where land portion 40 has both outlet ports 74 and 76 closed. At this time, the

pressurizedfluid passing into valve housing 32, through inlet port 44, effects movement of valve 34 to the right as viewed in FIG. 6 of the drawings. The initial movement of piston 34, communicates inlet port 42 with outlet port 74, via groove 36, but assuming rotor 16 is in the position shown in FIG. 6, the flow of pressurized fluid through conduit 48 into working chamber B is ineffective to cause rotor 16 to rotate. In this rotor position, working chamber B is in communication with exhaust port 24A and therefore pressurized fluid entering chamber B cannot apply a torque force on rotor 16. Accordingly, rotor 16 is not rotated until piston 34 is moved to a position where outlet port 76 is brought into communication with inlet port 42. At this time the pressurized fluid is conducted, via conduit 50, into working chamber C which is substantially fluid tight so that the pressurized fluid applies a torque force to effect rotation of rotor 16 in the direction of the arrow T. This rotation of rotor 16, through the interconnection (not shown) of the rotor and intake valve 28 and 28A, causes intake valve 28 to move to an open position so as to admit pressurized fluid into working chamber A which, in the position shown in FIG. 7, assists the pressurized fluid in working chamber C in applying a torque force to rotor 16. The piston continues to move to the right as viewed in FIG. 1 so that land portion 38 covers and seals outlet port 76 as well as outlet port 74.

As long as pressurized fluid remains in pipes 54 and the housing cavity and, therefore, maintains a force on end surface 58, piston 34 is held in an inoperative position where both outlet ports 74 and 76 are closed by land portion 38.

If in starting expansion engine 10, rotor 16 is in the position shown in FIG. 8 or 9, self-starter system 70 effects rotation of rotor 16 when piston 34 is moved to a position where it communicates intake port 42 with outlet port 74 so as to supply pressurized fluid to chamber A which is substantially fluid tight in these positions of rotor 16.

It is now believed readily apparent that the present invention provides a self-starter system for a single rotor, rotary expansion engine of the type having a planetary rotor, which system is relatively simple and automatically becomes operative in response to the flow of pressurized driving fluid. It is also a system which automatically becomes inoperative when the engine is being driven by pressurized driving fluid delivered through the intake ports of the engine.

Although but one embodiment of the invention has been illustrated and described in detail, it is to be expressly understood that the invention is not limited thereto. Various changes can be made in the arrange ment of parts without departing from the spirit and scope of the invention as the same will now be understood by those skilled in the art.

What is claimed is:

1. A self-starter system for an expansion rotary engine of the planetary rotor type having a rotor within a housing cavity and defining with the housing a plurality of working chambers and in which pressurized driving fluid from a source thereof is conducted through intake ports to said working chambers to rotatively drive the rotor, the self-starter system comprising:

a. a conduit means separate from said-intake ports communicating with said source of pressurized fluid and at least one of said working chambers which is substantially fluid tight and against which the pressurized fluid exerts a torque force; and

b. valve means in said conduit means for controlling fluid flow therethrough and responsive to pressurized fluid from said source thereof to move from a closed position to an open position to permit flow of pressurized fluid therethrough and to said at least one working chamber.

2. The apparatus of claim 1 wherein said valve means after movement to an open position is moved to and held in the closed position so long as pressurized fluid is conducted to the working chambers through said intake ports.

3. The apparatus of claim 1 wherein said conduit means is a passageway of relatively small flow area.

4. The apparatus of claim 1 wherein said valve means comprises a piston disposed for reciprocation within a housing cavity, a first passageway means communicating with the source of pressurized fluid with the housing cavity on one side of the piston to apply a force against said piston to move the latter to said open position, a second passageway means having a flow restriction therein communicating a low pressure area to the housing cavity on the opposite side of said piston.

5. The apparatus of claim 4 wherein biasing means is provided to urge the piston to said closed position.

6. The apparatus of claim 5 wherein said biasing chambers through two intake ports to rotatively drive the rotor, two exhaust ports being provided to expel spent pressurized fluid from the working chambers, the self-starter system comprising:

a. first conduit means separate from said intake ports communicating with said source of pressurized fluid and one of said working chambers;

b. second conduit means separate from said intake ports communicating with said source of pressurized fluid and another of said working chambers;

c. each of said first and second conduit means communicating with their-associated chambers so that pressurized fluid passed into the associated chamber exerts a torque force on said rotor;

d. valve means disposed to control flow of pressurized fluid through said first and second conduit means and responsive to pressurized fluid from said source thereof to move from a closed position to an open position to permit flow of pressurized fluid therethrough and into said first and second conduit means and thereby effect rotation of said rotor.

8. The apparatus of claim 7 wherein said valve means is a piston-cylinder device.

9. The apparatus of claim 8 wherein said piston has two spaced land portions and is disposed for reciprocative movement in said cylinder.

10. The apparatus of claim 7 wherein said valve means comprises a housing defining a cavity, a piston disposed for reciprocative movement in said cavity, a first port means in said housing communicating with said source of pressurized fluid and said cavity to pass pressurized fluid into the cavity when the piston moves to the open position thereby communicating said first port means with said first and second conduit means, a second port means in said housing communicating with said source of pressurized fluid and said cavity to pass pressurized fluid into the cavity so that a force is exerted on the piston to move the piston to positions communicating said first port means with said first and second conduit means, and a third port means in said housing communicating the cavity ahead of said piston movement with a low pressure area.

11. The apparatus of claim 10 wherein said piston is spring biased in a closed position.

12. The apparatus of claim 10 wherein said piston functions to admit pressurized fluid sequentially through said first and second conduit means.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION PATENT NO. I 3,847,514

DATED 1 November 12 19 74 INVENTOR(S) Hsin S. Chen and Charles Jones It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

IN THE SPECIFICATION:

Column 1, line 18, after the Word'torque insert the word orce--. Column 2 line 15 the word "rotor" should be --ratio-- line 67, the word "retracted" should be -restricted--. Column 5, line 24, the word "pressure" should read -pressurized--.

Signed and sealed this 3rd day of June 1975.

(SEAL) Attest:

v C. MARSHALL DANN RUTH C. MASON Commissioner of Patents Attesting Officer and Trademarks 

1. A self-starter system for an expansion rotary engine of the planetary rotor type having a rotor within a housing cavity and defining with the housing a plurality of working chambers and in which pressurized driving fluid from a source thereof is conducted through intake ports to said working chambers to rotatively drive the rotor, the self-starter system comprising: a. a conduit means separate from said intake ports communicating with said source of pressurized fluid and at least one of said working chambers which is substantially fluid tight and against which the pressurized fluid exerts a torque force; and b. valve means in said conduit means for controlling fluid flow therethrough and responsive to pressurized fluid from said source thereof to move from a closed position to an open position to permit flow of pressurized fluid therethrough and to said at least one working chamber.
 2. The apparatus of claim 1 wherein said valve means after movement to an open position is moved to and held in the closed position so long as pressurized fluid is conducted to the working chambers through said intake ports.
 3. The apparatus of claim 1 wherein said conduit means is a passageway of relatively small flow area.
 4. The apparatus of claim 1 wherein said valve means comprises a piston disposed for reciprocation within a housing cavity, a first passageway means communicating with the source of pressurized fluid with the housing cavity on one side of the piston to apply a force against said piston to move the latter to said open position, a second passageway means having a flow restriction therein communicating a low pressure area to the housing cavity on the opposite side of said piston.
 5. The apparatus of claim 4 wherein biasing means is provided to urge the piston to said closed position.
 6. The apparatus of claim 5 wherein said biasing means is a spring.
 7. A self-starter system for an expansion rotary engine of the planetary rotor type having a rotor of generally triangular profile eccentrically supported for rotation within a housing cavity of two-lobe trochoidal configuration and defining with the housing cavity three working chambers and in which pressurized driving fluid is conducted from a source thereof to the working chambers through two intake ports to rotatively drive the rotor, two exhaust ports being provided to expel spent pressurized fluid from the working chambers, the self-starter system comprising: a. first conduit means separate from said intake ports communicating with said source of pressurized fluid and one of said working chambers; b. second conduit means separate from said intake ports communicating with said source of pressurized fluid and another of said working chambers; c. each of said first and second conduit means communicating with their associated chambers so that pressurized fluid passed into the associated chamber exerts a torque force on said rotor; d. valve means disposed to control flow of pressurized fluid through said first and second conduit means and responsive to pressurized fluid from said source thereof to move from a closed position to an open position to permit flow of pressurized fluid therethrough and into said first and second conduit means and thereby effect rotation of said rotor.
 8. The apparatus of claim 7 wherein said valve means is a piston-cylinder device.
 9. The apparatus of claim 8 wherein said piston has two spaced land portions and is disposed for reciprocative movement in said cylinder.
 10. The apparatus of claim 7 wherein said valve means comprises a housing defining a cavity, a piston disposed for reciprocative movement in said cavity, a first port means in said housing communicating with said source of pressurized fluid and said cavity to pass pressurized fluid into the cavity when the piston moves to the open position thereby communicating said first port means with said first and second conduit means, a second port means in said housing communicating with said source of pressurized fluid and said cavity to pass pressurized fluid into the cavity so that a force is exerted on the piston to move the piston to positions communicating said first port means with said firsT and second conduit means, and a third port means in said housing communicating the cavity ahead of said piston movement with a low pressure area.
 11. The apparatus of claim 10 wherein said piston is spring biased in a closed position.
 12. The apparatus of claim 10 wherein said piston functions to admit pressurized fluid sequentially through said first and second conduit means. 